Months of aftershocks from Vic 5.8 quake

The aftershocks from Wednesday's quake have largely ranged between a magnitude 2.0 and 3.0.
The aftershocks from Wednesday's quake have largely ranged between a magnitude 2.0 and 3.0.

A magnitude 5.8 earthquake that struck Gippsland is the largest onshore quake in Victoria's recorded history and aftershocks could go on for months.

Aftershocks have already struck every few minutes since the 9.15am tremor between Woods Point and Licola North in the state's east, the largest being a 4.7 quake 18 minutes after the first.

"That in itself would've been a pretty exiting day but it was overshadowed by the 5.8," Seismology Research Centre chief scientist Adam Pascale told AAP.

He expects aftershocks, which have largely ranged between a magnitude 2.0 and 3.0, to continue for months.

"We're talking aftershocks that people may not feel ever, but earthquakes of this magnitude we've had before go on for years," he said.

Seismological instruments were still recording aftershocks from a magnitude 5.2 earthquake near Baw Baw in 1996, he said.

It's also possible that Wednesday's shake might be a foreshock for a larger earthquake.

The initial Baw Baw earthquake was a magnitude 3.5, which was followed 90 minutes later by a magnitude 5.0, while a 4.7 magnitude quake at Korumburra in 2009 was followed with another of the same size two weeks later.

"It's always possible that this is not the largest event of the sequence," he said.

"But it's unlikely. What we've seen in the past when we've had events of this sort of magnitude is they usually tail off with smaller aftershocks."

While the quake and the aftershocks have centred on the same area, Mr Pascale said it was not surprising it had been felt so far away.

There were reports of shaking being felt across Victoria, at Canberra's Parliament House, central Sydney, northern Tasmania and parts of Adelaide.

Mr Pascale said he had even heard reports of it being felt in Newcastle, which was devastated by a magnitude 5.6 earthquake in 1989.

Because the southeast of Australia is part of a stable continental region of old, hard rock, the energy from a quake travels further.

"A magnitude 5.8 in California wouldn't be felt anywhere near as far as in southeast Australia."

Adrian McCallum, a geotechnical engineering lecturer at the University of the Sunshine Coast, said the Australia's continental plate was moving about 7cm north a year, building compressive stress that was released through earthquakes.

He said Mansfield had a large number of fault lines, making it more probable an earthquake would occur there.

Damage from the quake was seen in Melbourne's Chapel Street, where part of a brick wall toppled into the street.

Michael Griffith, a structural engineering professor at the University of Adelaide, said many unreinforced brick masonry buildings were built long before earthquake design requirements were put in place.

New Zealand has mandated that existing buildings be strengthened to protect against earthquakes.

While Australia has not, he said research was being done to develop cost-effective ways of preventing damage like what occurred in Chapel Street.

Australian Associated Press